This invention relates to laminated materials suitable for use on protective clothing to guard against hazardous material (HAZMAT) exposure, while also providing flash protection.
In most HAZMAT control operations, a hazardous material specialist (hereinafter "fire fighter") is confronted with at least two possible hazards. The first hazard is the exposure to and subsequent skin contact with toxic or corrosive chemicals or materials. The second hazard is the exposure to sudden, intense flashes of fire and heat.
Various protective clothing is known in the art to prevent skin contact with toxic agents. Some of this clothing is made out of laminated material such as the material described in Nuwayser, U.S. Pats. No. 4,214,321 and Athey, Jr., 4,588,646. The purpose of using a laminate material is to create a composition that contains the most desirable properties of the individual layers. For example, a material may be a composite of a chemcially resistive barrier to prohibit the passage of the chemical through the material, and a substrate material that strengthens the chemical resistive barrier so that the composite can be used to make clothing.
Various laminates have been created to provide protection from chemicals having a variety of chemical properties. For example, the Mine Safety Appliances Company (MSA) of Pittsburgh, Pennsylvania sells two different protective suits. The first suit is comprised of a three-layer material of Viton.RTM. (registered trademark of E. I. duPont de Nemours Co.) on a nylon substrate on neoprene. This suit is used for cleanups of spills such as, for example, benzene or gasoline. The second type of suit manufactured by MSA is comprised of a different three-layer material of butyl on polyester on neoprene. This laminate composition is effective for use in cleaning spills such as acetone or chlorine.
However, none of the previously aforementioned clothing provides protection against sudden heat flashes. Sudden heat flashes can occur when oxygen suddenly becomes available to a flammable source, or when a chemical reaches its ignition temperature.
There are three types of heat that accompany such sudden fire flashes. The first type is convective heat such as the heat that the body would sense in a sauna. Convective heat occurs when the body is in direct contact with the heat source or flame. The second type is conductive heat such as the heat experienced by the body when it would come in contact with, for example a heating pad. Conductive heat requires a conduction medium such as air or water or, as in the present example, the heating coil and material in a heating pad. The third type of heat is radiant heat such as the heat generated by the sun or a sun tan bed. The most intense radiant heat occurs upon combustion of the material. Radiant heat has a higher specific heat than convective or conductive heat and therefore can be much more dangerous to the fire fighter than conductive or convective heats.
A sudden heat flash contains both convective heat (flames) and radiant heat (radiant energy). A flash may be short lived, however, it can generate enough heat to seriously burn or kill a fire fighter. In order to minimize the amount of heat that is absorbed by the body of the fire fighter, the fire fighter can wear a protective suit that is made from a material that reflects the heat.
Many flash protection suits are commercially available. The suits are comprised primarily of a metal foil or reflective layer attached to a substrate for strength. The foil or reflective layer acts to prevent the body from absorbing the heat energy by reflecting the energy away from the body. The principal is much the same as using a light colored roof to reflect heat from the sun away from the roof rather than a black roof that will absorb the sun's heat into the roof.
Previously, when confronted with fighting fires caused by HAZMAT spills or fighting fires in chemical plants, the fire fighter had to decide whether to wear a chemically resistant suit to guard against chemical splash or to wear a flash protection suit to guard against sudden fire flashes. With either choice, the fire fighter was in peril of being exposed to the other hazard. It has thus been desirable to provide a single protective suit that could guard against both chemical splashes and fire flashes. The present invention provides a single suit that provides protection against both.